Animal food composition

ABSTRACT

A breath-freshening pet food composition comprising at least 40 ppm by weight of one or more plant extract(s), preferably selected from essential oils.

This invention relates to a breath-freshening pet food for a domesticanimal, particularly for a dog. In particular, the invention relates toa breath-freshening biscuit.

Halitosis (bad breath or oral malodour) is a common problem amongdomestic pets such as dogs and cats and constitutes a significantpsycho-sociological problem in the animal-owner relationship. Moststudies of halitosis, however, have dealt with the problem in humans.Current thinking suggests that the predominant source of bad breath inhumans is the mouth. This is supported by experimental findings whichshow that oral hygiene procedures such as tooth brushing markedlydecrease malodour, while conditions such as caries and periodontitisincrease the incidence and intensity of oral malodour [G. F. Sulser, R.H. Brenning and L. S. Fosdick, J. Dental Research, 18: 355-359 (1939)].

Although few studies have been published specifically on oral malodourin companion animals, as with humans the root cause in most cases liesin the animal's relatively poor oral hygiene. Very few owners brushtheir dog's teeth or have them cleaned by a veterinary surgeon on aregular basis.

Oral malodour is produced as a result of microbial metabolism ofexogenous and endogenous proteinaceous substrates. No singlemicro-organism has been indicated as the primary cause. Theproteinaceous substrates can be derived from food debris, exfoliatedoral epithelium, saliva, blood and gingival crevicular fluid. Theproteins obtained from these sources undergo proteolysis to peptides andamino acids which are further metabolised to highly volatile compounds.It is these volatile compounds which are perceived as oral malodour. Ithas been shown that the predominant unpleasant-smelling components ofbad breath are volatile sulphur compounds or VSCs [J. Tonzetich, J.Periodontology, 48: 13-20 (1977)], the most significant being hydrogensulphide (H₂S) and methyl mercaptan (CH₃SH).

There is an abundance of remedies for bad breath and improving oralhygiene in humans. U.S. Pat. No. 5,472,684, for example, discloses ananti-bacterial oral composition for counting plaque and gingivitiscomprising thymol and eugenol and, optionally, flavouring agents such asAustralian Tea Tree Oil. However, many of these types of remedy, such asmouthwashes, sucking mints or chewing gum, or even chewing parsleyleaves, are of little value for use with a domestic animal, since theyrequire a significant residence time in the mouth. Clearly domestic petssuch as dogs lack the discipline and understanding necessary to make useof these approaches and, as most dog owners will testify, will consumemost food offered to them very rapidly.

The addition of breath-freshening active ingredients to pet foods toreduce oral malodour is known. CH-676200 discloses the use of zinccitrate, and other active ingredients such as chlorophyll, forincorporation into hard baked biscuits for dogs and cats. U.S. Pat. No.5,405,836 discloses the topical application of water soluble zinc salts,such as zinc sulphate, zinc gluconate and zinc chloride, to the surfaceof a dog biscuit. It is disclosed that topical application of the activeingredient to the biscuit is more effective in relation to incorporationof the active ingredient into the biscuit, i.e. in relation to theaddition of the active ingredient before baking. The activity of thezinc salts is attributed to a chemical reaction rather than toanti-bacterial action. The chemical reaction is between the zinc and theVSCs responsible for the oral malodour to form a non-volatile entity.Such biscuits are reported to produce significant reductions in badbreath in dogs.

There is a limit to the amount of the active ingredient that may beadded to the pet food. If the active ingredient is added above a certainlimit the food becomes unpalatable for the animal. In addition, the useof too great an amount of active ingredient may be harmful to the animaland increases the cost of manufacture. The object of the presentinvention is to provide an improved breath-freshening pet food which ishighly palatable for the animal.

According to the present invention there is provided a breath-fresheningpet food composition which contains at least about 40 ppm, preferably 60ppm, more preferably 80 ppm, more preferably 100 ppm, more preferably120 ppm, more preferably 160 ppm and more preferably 200 ppm by weightof the composition of one or more plant extracts. It is preferred thatthe pet food composition comprises no more than about 800 ppm,preferably 650 ppm, more preferably 500 ppm, more preferably 350 ppm,and more preferably 200 ppm by weight of the composition of the plantextract(s). In an embodiment of the invention, the pet food comprisesabout 200 ppm of one or more plant extracts by weight of the foodcomposition. The food is highly palatable and has the effect offreshening the pet's breath. The food is particularly suitable forconsumption by domestic pets, particularly dogs and cats.

According to a further aspect of the invention, there is provided aprocess for preparing the breath-freshening pet food composition of thepresent invention. The pet food compositions of the present inventionmay be made according to conventional methods well-known to thoseskilled in the art. The compositions may comprise, in addition to theplant extract(s), ingredients and additives substantially similar tothose used in conventional pet foods. The plant extract(s) may be addedto the pet food composition at any stage of its manufacture. However, ifthe plant extract(s) are added before the composition undergoes aheating step, an excess amount of plant extract, relative to the amountof plant extract desired in the final composition, should be added inorder to take into account the volatility of the plant extract(s).

It is preferred that the pet food of the present invention is a dry orsemi-moist pet food, preferably a biscuit. The manufacture of such petfoods and particularly pet biscuits generally involves the step ofshaping and baking a dough containing the desired ingredients. Thebreath-freshening biscuits of the present invention can be made from anysuitable dough according to conventional techniques known in the art.The plant extract(s) are generally added to the dough before baking and,accordingly, if the plant extract is volatile the dough should contain ahigher concentration of plant extract than is desired in the finalbiscuit. Typically, the dough should contain the plant extract(s) in anamount which is between 2 and 10 times greater than that required in thefinal biscuit. The precise amount of plant extract(s) added to the doughwill depend, inter alia, on the temperature and duration of heating, onthe size of the biscuit and on the volatility of the plant extract(s)used.

In an embodiment of the invention, the term “dry pet food” as usedherein is intended to mean a pet food having a water activity A_(w) ofless than 0.65. In this embodiment, the term “semi-moist pet food” asused herein is intended to mean a pet food having a water activity A_(w)of from about 0.65 to about 0.86. Water activity is a measure of therelative humidity above a sample of the pet food. The relative humidityis measured above a sample in a sealed chamber after being allowed toequilibrate. A device which is suitable for measuring these parametersis the Rotronic Hygroskop DT™. The water activity is on a scale of 0 to1.0 and is defined as:

water activity A _(w)={fraction (1/100)} (relative humidity)

The water activity reflects the amount of water which is available tomicro-organisms for growth and multiplication. At a water activity ofless than 0.65, it is not usually necessary to add preservatives to thepet food. At a water activity of from about 0.65 to about 0.86, it isdesirable to add preservatives to the pet food to prevent the growth ofmould although the growth of bacteria is minimal under such conditions.

The water content that corresponds to the water activities defined abovecan vary considerably depending upon a number of factors, such as thepresence and levels. of humectants (such as salt, sugar or glycerol etc)in the pet food. Typically, however, a “dry pet food” has a watercontent of less than about 15% by weight of the final biscuit and a“semi-moist pet food” has a water content of from about 15% to about 25%by weight of the final biscuit. Thus, in an alternative embodiment ofthe present invention, the term “dry pet food” as used herein means apet food which has a water content of less than about 15%, preferablyless than about 14%, by weight of the final biscuit. In this alternativeembodiment, the term “semi-moist pet food” as used herein means a petfood which has a water content of from about 15% to 25%, preferably fromabout 14% to about 25%, by weight of the final biscuit.

According to a further aspect of the invention there is provided the useof one or more plant extract(s) in the manufacture of a pet foodcomposition for reducing oral malodour in a domestic animal, wherein theplant extract(s) is/are present in an amount of at least 40 ppm byweight.

According to a further aspect of the invention there is provided amethod of reducing oral malodour in a domestic animal by theadministration to, or consumption by, the animal in need thereof of apet food composition which contains at least about 40 ppm by weight ofthe composition of one or more plant extracts.

The term “plant extract” as used herein is intended to mean anysubstance which is derived, obtained or extracted from a plant or plantpart by conventional separation techniques. In a preferred embodiment,the term “plant extract” as used herein is intended to mean anysubstance which is derived, obtained or extracted from a plant or plantpart by conventional separation techniques and which has anti-bacterialactivity. In a further preferred embodiment the term “plant extract” isintended to mean a substance selected from essential oil(s), oleoresins,absolutes and fruit juices. In a particularly preferred embodiment, theplant extract(s) are selected from essential oil(s).

An essential oil is the volatile etherial fraction obtained from a plantor plant part by a physical separation method. The physical separationmethod usually involves either distillation (including waterdistillation, steam distillation, water and steam distillation and drydistillation) or expression (pressing). Enfleurage, a process in which afloral material is adsorbed onto fat and the essential oil obtained byalcoholic extraction from this fat, may also be used to obtain theessential oil. Generally, essential oils represent the odorous part ofthe plant material.

Essential oils include angelica root, aniseed, basil, bay, bergamot,bergamot Furocoumarin Free (FCF), cajeput, camphor, cardamom, carrot,cassia, cedarwood (Atlas), cedarwood (Chinese), cedarwood (Texas),cedarwood (Virginia), celery, chamomile, clary sage, clove bud, cloveleaf, cinnamon leaf, coriander, cumin, dill, eucalyptus, fennel,frankincense, geranium, ho-wood, lavender, lemongrass, lemon, litsea,marjoram, melissa, myrrh, myrtle, niaouli, neroli, nutmeg, orange(including sweet orange), palmarosa, patchouli, peppermint, petit grain,pimento berry, pine needle, ravensara aromatica, rosewood, rosemary,sage (Dalmatian), tea tree, thyme (including red thyme) and verbena. Thepreferred essential oils for use in the present invention areeucalyptus, lemongrass, bay, cinnamon, lavender, thyme, clove bud andteatree. Eucalyptus and lemongrass oils are most preferred.

The term “oleoresin”, as used herein, is intended to mean the fractionobtained by solvent extraction from spices and herbs. The term“absolute”, as used herein, is intended to mean the fraction obtained byextrusion using alcoholic solvent. Absolutes are generally manufacturedby alcoholic extrusion from an oleoresin. The term “fruit juice”, asused herein, is intended to mean the fraction obtained by expression ofthe whole fruit or of the flesh of the fruit. (In contrast, an“essential oil” obtained by expression from a fruit is usually obtainedby the expression only of that part of the fruit in which the oil ismost concentrated, for example in the peel of an orange or lemon).

The plant extracts are either available commercially or may be obtainedfrom the plant or plant part by conventional separation techniques, asdescribed above.

The efficacy of the plant extracts in treating oral malodour is believedto arise from their anti-bacterial activity.

The use of eucalyptus oil in human oral hygiene products, such asmouthwashes, is well known. However, the successful use of theseproducts depends on the presence of the product in the mouth for acertain minimum time period. The use of eucalyptus oil or other plantextract would not be expected to provide a benefit to domestic petsbecause of the very short time during which the food is present in theanimal's mouth prior to swallowing and because of the incorporation ofthe oil into the food (e.g. a biscuit) as opposed to a liquid format.

The determination of the levels of VSCs provides a quantitative measureof the extent of oral malodour. The breath-freshening effects of the petfoods of the present invention were determined objectively by measuringreductions of the levels of VSCs in the animal's breath at variousintervals after consumption. In addition, the anti-bacterial effect ofvarious essential oils was also determined.

The invention will now be described in detail for dog biscuits, but thedescription applies generally to dry pet foods such as pelletized dog orcat foods, main meals (e.g. extruded pet foods having 6 to 8 percentmoisture), etc.

The dog biscuits can be made from conventional dog biscuit doughs. Thedough can comprise at least one flour, meal, fat and water. Aconventional dough for dog biscuits may also contain discrete particlesof meat and/or meat byproducts or farinaceous material. Such doughstypically contain fat solids. Examples of suitable doughs for theproduction of hard dog biscuits are disclosed in U.S. Pat. Nos.4,454,163 and 4,743,459, and suitable doughs for the production of softdog biscuits (containing humectant to control water activity) aredisclosed in U.S. Pat. No. 4,454,164. The disclosures of such doughs andthe manufacture of pet food disclosed in U.S. Pat. Nos. 4,454,163,4,454,164 and 4,743,459 are incorporated herein by reference.Particulate proteinaceous particles, such as particles of meat,texturized vegetable protein and/or meat byproducts, can be incorporatedto add flavour to the biscuits and texturize the surface. (See U.S. Pat.No. 4,743,459, for example.) Particular farinaceous materials, such asbran particles, can also be employed to texturize the interior and/orsurface or the biscuits and to provide other useful properties to theproduct. A dough found to produce biscuits highly palatable to dogsincludes suitable proportions of wheat flour, wheat meal, soybean meal,meat and bone meal, animal fat and natural flavours in admixture withwater. The meal used in the doughs suitable for production of biscuitsof the invention can comprise meat and/or bone and/or vegetable matterincluding farinaceous materials, materials prepared from legumes such asbeans and peas, tuberous materials such as potato meal, and the like.The meals can be finely or coarsely ground as desired for the texture.Flours made from any suitable farinaceous material can be used.

A suitable dough contains farinaceous material, an edible oil, anantioxidant, an antimycotic, salt, animal fat added vitamins andminerals, such as those disclosed in U.S. Pat. No. 4,229,485, column 5,lines 7 to 57, which is incorporated herein by reference. Thecompositions of the invention may also contain at least oneanimal-derived proteinaceous meal such as meat meal, bone meal or fishmeal. A good biscuit dough for producing the biscuits of the inventioncontains about 50 to 60 percent by weight of wheat flour, about 5 to 10percent by weight of soybean meal, about 3 to 10 percent by Weight ofmeat and bone meal, about 1 to 5 percent of wheat meal, about 1 to 5percent of animal fat preserved with BHA, about 20 to 30 percent byweight of water, about 2 to 5 percent by weight of natural flavours,vitamin and mineral preblend, and acidulant

The dough ingredients are generally admixed at a temperature of about 5°to about 60° C., preferably about 15° C. to about 30° C.

The dog biscuit doughs can contain a softening agent or humectant. Thepreferred humectant is propylene glycol. Examples of other humectantswhich can be used are corn syrup, sugar and polyalcohols, such assorbitol and glycerin.

The dough can also contain edible surfactants or emulsifying agents,e.g. cationic agents and nonionic agents. Exemplary nonionic emulsifyingagents can be broadly defined as compounds produced by the condensationof alkylene oxide groups (hydrophilic in nature) with an organichydrophobic compound which can be aliphatic, alkyl aromatic, or acondensate of an alkylene oxide with an alkylene glycol (hydrophilic innature). Examples of nonionic emulsifying agents which can be usedinclude polyethylene oxide condensates of alkyl phenols, productsderived from the condensation of ethylene oxide with the reactionproduct of propylene oxide and ethylene diamine, ethylene oxidecondensates of aliphatic alcohols, long chain tertiary amine oxides,long chain tertiary phosphine oxides, long chain dialkyl sulfoxides andmixture of such materials. The emulsifier is generally used in minoramounts.

The dog biscuit dough can be mixed using conventional equipment. Forexample, the mixing can be at 20 to 100 rpm. For example, a dry blendingstep can be done at room temperature for a period of time of about 3minutes to about 20 minutes. The dry-blended mixture can then be mixedwith water to form a first stage dough. The water which can be admixedwith the dryblended mixture is typically at a temperature of about 20°C. to about 65° C. The water can be added, with mixing, over a period oftime of about 3 minutes to about 6 minutes to form the first stagedough. Then, the fat portion of the biscuit dough can be admixed withthe first stage dough to form the final stage dough. The fat portion canbe added at a temperature at which it is at least fluid, typically atabout 35° C. to about 65° C. The fat portion can be mixed for a periodof time which is sufficient to form a dough whose homogeneity isvisually apparent. A typical final mixing time is about 3 to about 5minutes.

Formation of the dough is achieved at about atmospheric pressure withthe mixing of the components being conveniently achieved in an uprightsigma blade mixer or other bakery-type mixers. The various ingredientscan be added over a period of time or in a one-shot process according tothe above order of addition. However, melted fat and water can be addedsimultaneously and mixed for about 6 to 10 minutes.

The dog biscuits are formed in any conventional or suitable manner, suchas by extrusion, stamping, cutting or molding. Any suitable dog biscuitshape, such as a bone-shaped biscuit, can be used. For many products,such as the bone-shaped canine biscuits of the invention, a rotarymolding system is preferred because it permits the rapid forming ofdough pieces with good control over their shape, form and surfacecharacteristics. Docker holes are optionally formed in the dough pieceduring molding to facilitate the escape of moisture during baking,cooking and/or drying.

The dough is formed into pieces by machining on a rotary molder withspecific die shapes. The dough can also be formed into pieces bysheeting followed by either a vertical or rotary cutter or by a rotarymolder. Suitable die and cutter shapes are those which result in biscuitproducts having bone, round, square, triangular, T-bone or chop shapesand the like. The forming is achieved at conventional temperatures ofambient to about 45° C. and pressures of less than about 5½ kg/cm², usedwith a rotary molder, a vertical cutter or rotary cutter.

The dough pieces can be baked using any suitable or conventionalequipment and conditions. For example, the dough pieces can be passedinto a conventional oven where the biscuit is baked. The conveyer beltsof the oven can be coated with an edible lubricant, such as a natural orsynthetic cooking oil or shortening, to facilitate separation of theconveyer belts of the baked product. Temperatures in the range of about100° C. to about 300° C. can be used. The baked biscuits can also besubjected to subsequent drying at temperatures of about 90° C. to 200°C. either within the baking oven or separately, to produce the desiredmoisture content in the final product. Baking and drying temperaturesand times are those conventionally used in the production of a caninebiscuit. Typically, baking temperatures and times for a hard, dry caninebiscuit are about 100° C. to about 250° C. for about 25 minutes to about8 minutes. Drying conditions for a hard, dry canine biscuit aretypically about 90° C. to about 160° C. for about 25 minutes to about 12minutes in a forced air dryer. On a weight basis, the moisture contentof the final dry biscuit is preferably less than or equal to about 15percent by weight and preferably about 10 to 12 percent by weight of thefinal biscuit at 70 percent relative humidity.

The baking and drying process provides a shelf stable product withoutthe need of any moisture barrier protection.

The composition of the present invention is used to reduce oral malodourof pets, particularly dogs. For an average biscuit weight of 10 grams, arecommended biscuit intake is about 10 biscuits a day for a medium sizedog, which should supply about ¼ to ⅓ of a dog's calorific requirement.

The invention will now be described with reference to the followingexamples. It will be appreciated that what follows is by way of exampleonly and that modification of detail may be made without departing fromthe scope of the invention.

EXAMPLES Example 1

VSC Reduction

The following types of dog biscuit were prepared according toconventional techniques:

1. A plain biscuit

2. A plain biscuit +0.1% eucalyptus oil

3. A plain biscuit +0.05% copper chlorophyllin

4. A plain biscuit +0.18% zinc sulphate

The eucalyptus oil and the copper chlorophyllin were added into thebiscuit dough prior to forming and baking. The biscuit dough comprisedthe following ingredients:

Ground Wheat 30% Oats & Bran 17.5% Grits & Seeds 16.5% Gluten 7.5% Sugar6% Fat 5% Aromas, Flavours 7.5% Vitamins & Minerals 10%

The level of eucalyptus oil in the final product was 0.02% (i.e. 200ppm), with a large amount being lost in baking due to the volatility ofthe oil. The zinc sulphate was applied to the surface of the biscuitafter baking, as a 30% solution in water.

The biscuits were fed to a panel of 16 small and medium sized dogs, with1 biscuit per feeding being offered to dogs <10 kg in weight and 2biscuits per feeding to those >10 kg in weight. VSC measurements werecarried out immediately prior to feeding the biscuit(s), and 10 minutes,30 minutes and 3 hours after feeding.

Measurement of VSCs was performed using a portable sulphide monitor(Halimeter, Interscan Co.). This instrument contains an electrochemicalgas detector with a diffusion medium through which the air sample passesat a constant flow rate. The adsorption of VSC on an electrocatalyticsensing electrode generates an electric current directly proportional tothe gas concentration which is then displayed in parts per billion(ppb). The inlet of the Halimeter was connected to a 30 cm length ofteflon tubing. This was attached to a modified disposable syringe barrel(1 ml) which had a tear tip and finger tabs removed. The syringe barrelwas replaced with a clean one for each dog to prevent salivacontamination of the tubing. To sample the oral cavity the syringebarrel was placed between the dog's incisors to a depth of 2-3 cm,depending on the size of dog. The dog's mouth and lips were held closedon the syringe to prevent licking and panting. A single measurement wastaken and the VSC level (ppb) recorded when the reading on the Halimeterpeaked, usually after about 15-20 seconds.

Table 1 shows the average change in VSC levels (% change), relative tothis initial level, at the stated time intervals after feeding thebiscuits.

TABLE 1 Biscuit 10 mins 30 mins 180 mins 1 −1.6 −0.5 −0.9 2 −9.2 −14.4−9.1 3 −8.1 −13.7 −3.6 4 −5.8 −11.0 −7.9

Analysis of variance was used to determine the effect of the biscuitcomposition on VSC levels. It can be seen that all of the biscuitscontaining active ingredients produce a greater reduction in VSC levelsthan a plain (active-free) biscuit. However, the only result which issignificantly different from the plain biscuit is biscuit 2 (containingeucalyptus oil as the active ingredient), for which a 97% significance(p=0.03) is attained 30 minutes after feeding.

Example 2

Anti-bacterial Effect of Eucalyptus Oil Against Specific Bacteria

Four anaerobic bacteria, commonly associated with the generation of badbreath in humans, and believed to be associated with bad breath indomestic animals, especially dogs, were incubated with eucalyptus oilfor 24 hours (P. canoris) or 48 hours (all other bacteria) at 37° C.prior to plating out. The anti-bacterial effect of eucalyptus oil isevident from Table 2 which shows the susceptibility of the bacteria tothe oil. The data represent the log₁₀(Total Viable Count (TVC)) of thebacteria obtained after incubation. The TVC enumerations of thesecultures indicate that Eucalyptus oil has a significant detrimentaleffect on bacterial growth.

TABLE 2 ppm of Eucalyptus oil Organism 20 200 2000 20000 Porphyromonascanoris 8.41 8.49 8.7 3 Veillonella alcalescens 7.89 7.81 7.9 3.66Bacteriodes oralis 6.99 7.04 7.18 6.28 Fusobacterium nucleatum 7.23 7.237.04 —

Example 3

Anti-bacterial Effect of Various Essential Oils Against Bacteria inCanine Saliva Samples

The potential antibacterial activity of a variety of commerciallyavailable essential oils against oral bacteria in canine saliva sampleswas determined. Fresh (zero h control) and stagnated saliva (24 hincubation period) samples were examined, since work by Sulser, G. F. etal., (1940, Journal of Dental Research, 19, 1736), Prinz, H. (1930,Dental Cosmos 72, 700) and McNamara, T. F. et al., (1972, Oral Surgery34, 41) has demonstrated that a major source of offensive breath odouris saliva stagnation. In the present experiments, saliva stagnation andputrefaction was optimised by incubation for 24 h at 37° C.

Saliva from four Irish Setters was collected in sterile universalbottles (morning collection prior to feeding), and pooled before beingused within 2 h of sampling. The saliva was diluted 1:10 in MaximumRecovery Diluent (Merck) and duplicate aliquots placed in bijou bottles.The chosen undiluted essential oil was added (filter sterilised, 0.2 μmWhatman filter) to produce a final oil concentration of 10000 parts permillion of essential oil in each saliva sample. The tubes were mixedthoroughly. The samples were incubated at 37° C. for 24 h anaerobically.The control samples contained either (1) 2.0 ml fresh canine saliva withno added oil; or (2) 0.2 ml olive oil in place of essential oil.

For investigation of antimicrobial effects, 1 ml samples were removed atzero h and 24 h. A dilution series was prepared in Maximum RecoveryDiluent and the appropriate dilution plated out onto pre-reduced WilkinsChalgren agar. Plates were incubated anaerobically (Willins Chalgrenagar, anaerobic jar) at 37° C. for 24 h. Total viable anaerobic countswere read after this time.

The results of the tests are shown in Table 3. Lemongrass, bay,cinnamon, clove and thyme oils all exhibited a strong antibacterialeffect. Lavender, tea tree and rosewood oils showed a slightly milderanti-bacterial effect. The other oils mentioned in Table 3 all showed astatistically significant anti-bacterial effect in relation to the 24hour control sample.

TABLE 3 Zero hour and 24 hour readings Sample Colony Count Log₁₀ mlSaliva⁻¹ Zero h readings No added oil 7.1 24 h readings No added oil 9.9Olive 9.3 Bay 2.0 Cinnamon leaf 2.0 Clove bud 2.0 Coriander 8.0 Cumin8.0 Dill weed 7.7 Eucalyptus 8.7 Lavender 3.8 Lemongrass <1.0 Rosewood6.3 Tea tree 5.4 Thyme (red) 2.9

What is claimed is:
 1. A breath-freshening dry or semi-moist pet foodcomposition comprising at least 40 ppm by weight of one or more plantextract(s) selected from a group consisting of essential oil(s),oleoresin(s), absolute(s) and fruit juice(s), wherein the plantextract(s) is/are added to the pet food composition before the pet foodcomposition undergoes a heating step.
 2. A pet food compositionaccording to claim 1 which is a pet biscuit.
 3. A pet food compositionaccording to claim 1, wherein the plant extract(s) is/are the soleactive ingredient.
 4. A pet food composition according to claim 1,comprising at least 80 ppm by weight of plant extract(s).
 5. A pet foodcomposition according to claim 1, comprising at least 120 ppm by weightof plant extract(s).
 6. A pet food composition according to claim 1,comprising at least 200 ppm by weight of plant extract(s).
 7. A pet foodcomposition according to claim 1, comprising no more than about 800 ppmweight of plant extract(s).
 8. A pet food composition according to claim1, comprising no more than about 500 ppm weight of plant extract(s). 9.A pet food composition according to claim 1, comprising no more thanabout 200 ppm weight of plant extract(s).
 10. A pet food compositionaccording to claim 1 wherein there is one plant extract present.
 11. Apet food composition according to claim 1 wherein said plant extract(s)are selected from essential oil(s).
 12. A pet food composition accordingto claim 11 wherein the essential oil(s) is/are selected from a groupconsisting of eucalyptus oil, lemongrass oil, bay oil, cinnamon oil,lavender oil, thyme oil, clove bud oil and teatree oil.
 13. A pet foodcomposition according to claim 11 wherein the essential oil iseucalyptus oil.
 14. A pet food composition according to claim 11 whereinthe essential oil is lemongrass oil.
 15. A pet food compositionaccording to claim 1 which is a dog or cat food.
 16. A process ofmanufacturing a dry or semi-moist pet food composition for reducing oralmalodour in a domestic animal comprising the steps of: providing a petfood composition, wherein the pet food composition is a conventional dryor semi-moist pet food composition; adding one or more plantextract(s),wherein the plant extract(s) is/are present in an amount ofat least 40 ppm by weight and wherein the plant extract(s) is/areselected from a group consisting of essential oil(s), oleoresin(s),absolute(s) and fruit juice(s); and heating the pet food composition.17. A process according to claim 16 wherein the pet food composition isa pet food composition according to claim
 1. 18. A method of reducingoral malodour in a domestic animal by administration to, or theconsumption by, the animal in need thereof of a dry or semi-moist petfood composition according to claim 1.